This application claims the priority of German Patent Document No. 199 48 002.8, filed in Germany on Oct. 6, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a press, particularly to a press for massive forming.
Particularly in presses provided for massive forming, multi-station tools are frequently used. Workpieces travel through several tool stations successively. The traveling workpiece experiences a forming step in each tool station. The formings are achieved by a relative movement between the top tool and the bottom tool. The top tools of the tool stations are usually carried by a single common slide and therefore move synchronously in the same direction. Occasionally, however, forming operations are desired which require a movement of a movable member existing in the tool in a direction which deviates from the moving direction of the slide. Such movement is, for example, the movement of a shearing member by which edges, shaft ends or the like are cut off a correspondingly shaped workpiece. Such shearing operations must frequently be carried out in the last tool station. In this case, the movement of the shearing element takes place, for example, transversely to the linear movement of the slide.
In the working space of a corresponding press for massive forming, one or several transfer devices are also accommodated in addition to the tool. The transfer devices cause the transport of the workpieces from one press station to the next. The tools must leave a corresponding space for the transfer device. The transfer device is arranged along the tools, for example, on one of their sides. The opposite other side is required for the access to the tools. Therefore, when a movable tool existing in one tool part is to be connected with a driving device, these restrictions with respect to the existing space and the spaces to be kept free must be observed.
An object of the present invention is to provide a press with a suitable drive for a movably disposed forming element existing in the tool.
This object has been achieved by a press, particularly press for massive forming, having a press frame in which or on which a slide is movably disposed and is connected with a drive, having a workpiece receiving space in which the tool is arranged which has at least two tool parts having a forming device for which at least one forming element is arranged which is movably arranged in one of the tool parts, having a hydraulic force transmitting device which is connected with the forming element and is driven by the driving device.
The press according to the present invention has a tool receiving space in which a tool is arranged. The tool is divided into an upper and into a lower tool part. The upper tool part is connected with the slide of the press, while the lower tool part rests in the press. The tool may contain one or several tool stations. Furthermore, it is contemplated to provide a separate tool for each tool station, which tool will then, in each case, be divided into a lower and upper tool part. In this embodiment, the upper tool parts are connected with the slide and the lower tool parts, in turn, are connected with a bedplate. Furthermore, within the scope of the invention, it is also possible to provide only a single tool for a single forming station in the press. Irrespective of how many tool stations are arranged in the tool receiving space of the press, at least one forming element is present which is movably arranged in one of the tool parts and is driven by way of a hydraulic force transmitting device by the driving device of the press. This forming element has the purpose of, in addition to the forming movement, which is generated by the relative movement of the tool parts toward one another, carry out at least one other forming operation. Such a forming operation may, for example, be a shearing operation. At least one of the tool stations will then contain a shearing member which, at a desired point in time, carries out in a hydraulically operated manner a shearing operation on the workpiece. As a result, for example, in the last forming station, shaft ends, edges or other sections to be removed from the workpiece can be cut off.
As required and depending on its function and configuration, the forming element can be moved along a straight path or along a curved path. The fluid drive pertaining to the hydraulic force transmitting device is to be selected correspondingly. If a linear movement is required, a piston/cylinder arrangement is advantageously selected.
The hydraulic force transmitting device can be connected with the driving device in different manners. A particularly space-saving variant, which is easy to mount with respect to the tool, is obtained if the hydraulic force transmitting device is actuated by the slide. This slide establishes the required connection between the driving device and the hydraulic force transmitting device.
The hydraulic force transmitting device permits a flexible configuration so that otherwise required space can remain free. Furthermore, the working direction of the forming element can be advantageously liberally defined within wide limits. If the forming element is a shearing member, its working plane and working direction can be determined independently of the spatial arrangement of the hydraulic force transmitting device and particularly of its inlet section.
By the coupling of the forming element with the driving device by way of the hydraulic force transmitting device, a forced synchronization is caused between the slide and the forming element. A continuous coupling of the force transmitting device to the slide is not necessary. It is sufficient for this coupling to be established only when force is also to be transmitted.
The hydraulic force transmitting device comprises a pumping device which can be actuated, for example, by the slide, as well as a transmitting device which can be formed by fluid ducts in the corresponding tool part, and a fluid drive which is fed by way of the ducts and which is connected with the forming element. In this case, the fluid drive is preferably not fixedly connected with the forming element but only rests against it, so that the shearing forces are transmitted. This simplifies the tool construction and in a simple manner permits the demounting.
In most cases, the forming element is arranged in the bottom tool and is actuated in the proximity of the lower pressure point of the slide. In principle, it is also possible to provide such forming elements or forming devices in the top tool. In both cases, it is expedient for the hydraulic force transmitting devices to be actuated by a coupling device. The slide, for example, can be placed by way of a corresponding thrust piece (impact driver) on a push rod by way of which the force transmitting device is actuated. This will be useful when the forming element and the force transmitting device are accommodated in the lower tool part. If they are situated in the upper tool part, the corresponding push rod can, during the downward stroke of the upper tool part, be placed on a stationary stop, whereby, in turn, the actuation is triggered.
It is advantageous to combine the hydraulic force transmitting device with an overload safety device and, if necessary, combine the latter with a machine switch-off device. As a result, damage to the tool can be avoided.